1. Technical Field
The present invention generally relates to equipment used for forming bags and, more particularly, to equipment used to form and guide a tube of material before the material is formed into a bag. Specifically, the present invention relates to a former used to create square or rectangular tubes that are formed into bags.
2. Background Information
Various types of flexible packaging are formed with square or rectangular cross sections. These types of flexible packaging are commonly used in fast food retail establishments, grocery stores, and as lunch bags.
These bags are commonly formed by transforming a flat sheet of material into a tube that is folded into the bag. The material may be a polymer material, a metal material, or paper material. In order to form a bag with a square or rectangular cross section, the tube of material must have the same cross section. In prior art forming apparatus, the material used to form the bag would be drawn from a rolled supply of material and rolled over into a tube around a former that has the same cross section of the bag. In square and rectangular applications, the former would have the relatively sharp corners that are used to form the longitudinal corners of the bag.
A problem with this type of former is that the material being wrapped around and drawn over the former tears on the corners. The frequency of tearing increases as the drawing speed increases. The frequency of tearing also increases as the strength of the material decreases. As bag customers desire inexpensive bags, manufacturers are forced to use thinner materials run at higher speeds. This combination greatly increases the frequency of material tears. Each material tear requires the manufacturer to clear and reset the forming apparatus incurring significant downtime. In order to reduce these tears, the manufacturer must run the apparatus at a slow speed. The slow speed decreases the efficiency of the apparatus and bag manufacturers desire an apparatus that allows the speed of the apparatus to be increased while reducing the frequency of the tears.